Study On Patriculate Oxidation Catalyst Up To Chinese PhaseⅣ Standard For Diesel Engine

Harmful exhaust emission from cars belong to one of the important source ofenvironmental pollution,in the face of the current environmental and energy problems,countries racing issued more and more stringent vehicle emission regulations, thepurpose is to limit car exhaust pollution to the environment. Diesel engine exhaustemissions of the main pests of CO、HC、NOx and PM, NOx and PM havecontradictions between the relations,in the face of such contradictory relations,internal combustion engine scholars have been in the pursuit of a good compromisebetween relations. Currently only rely on internal purification technology can’t meetthe requirements of increasingly stringent emission regulations, must be within themachine technology can be met with closed purification technology. The main closedpurification technology includes: Diesel Oxidation Catalyst (DOC), Diesel ParticulateFilter (DPF), Selective Catalytic Reduction (SCR), Particulate Oxidation Catalyst(POC). In the face of so many excellent after-treatment technology, choose to suit therequirements of the present domestic development are the main, through comparingthe advantages and disadvantages, choose POC after-treatment as the research objectin this paper.Specific work content summarized as follows:1.Choose POC after-treatment samples, in CA6DL2-35E3type turbochargedinter-cooled making steady working condition of ESC cycle13heavy-duty dieselengine bench experiment, select samples in a relatively optimal after-treatment isanalyzed, after analysis under various working point POC after-treatment CO, HC,PM on emissions.The test done in10POC sample data analysis, the calculation ofPOC-6after-treatment of harmful gases and particles conversion efficiency comparedwith the other samples, after-treatment POC-6PM emissions from the original0.073g/kw.h to0.027g/kw.h, for PM conversion efficiency is63%;For HC emissions from the original0.162g/kw h to0.102g/kw.h, the conversion efficiency of HC is37%;ForCO emissions from the original1.271g/kw.h to0.233g/kw.h, of CO conversionefficiency is81.67%.Data emissions compared with IV emissions, HC emissionsbelow IV0.46g/kw.h, CO emissions below IV1.5g/kw.h, PM emissions than IV0.02g/kw.h, CO and HC can achieve IV emission standards, PM cannot reach the nationalstandard.Our results suggest the next step in the specific optimization are as follows:increase the number of carrier (encryption method rather than increasing volumemethod), increase the content of catalyst, optimizing the structure of coating andimprove catalyst oxidation and so on.2.Through the optimization of the three sample data, this paper compares andanalyzes the POC-101samples after purification ability of processor itself is superiorto other samples, POC-101pairs of particles (PM) conversion efficiency of76.9%,conversion efficiency of carbon monoxide (CO) is77.7%, the hydrocarbons (HC)conversion efficiency is32.4%.Illustrate the improvement after-treatment POC canmeet the requirements of IV, but because of poor stability of POC various conditions,to get the final results still need a lot of test, in almost all less.3.Analyze the POC-101, analysis of inlet temperature an，the air-fuel ratio，power and exhaust flow on the conversion efficiency.Inlet temperature under thecondition of A, B, C speed, with the increase of load inlet temperature graduallyraised, and the higher conversion efficiency.Air-fuel ratio under A, B, C speed withthe increase of load, air-fuel ratio is lower, the conversion efficiency is increased；Power under A, B, C speed with the increase of load, power linearly increased, theconversion efficiency increases, particulate emissions increase: exhaust flow under A,B, C speed with the increase of load, increase exhaust flow, increase efficiency.4.In the light of general pickup after installing POC processor under the NEDCcycle do wheel test test, the target from IV value far, concluded:(1)The measurementresults from the macroscopic, according to the current vehicle state only by improvingour POC performance reaches the national IV emission standard is impossible;(2) Wedesign the POC after-treatment the conversion efficiency does not meet the requirements, especially the PM and the low efficiency of HC is not ideal, if youwould like to further develop the independent product still needs to be furtherimproved after-treatment design and internal standard formula of catalysts.5.Install POC in the RMB80000km after-treatment do after aging test, under thesame distribution models under the same two road experiment, a light, a load of3tonsof cargo, concluded that when light aging degree than when the aging degree ofserious.